<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="icon" type="image/png" href="images/logo5.png" />
    <style>
        * {
            margin: 0px;
            padding: 0px;
        }
        /* .clearfix:before,
        .clearfix:after {
            content:"";
            display: table;
        }
        .clearfix:after {
            clear: both;
        }
        .clearfix {
            *zoom: 1;
        } */
        .top {
            height: 100px;
            background-color: gray;
        }
        .banner {
            height: 200px;
            width: 860px;
            background-color: pink;
            margin: 10px auto;
            

        }
        .a {
            width: 860px;
            background-color: pink;
            margin: 10px auto;
            overflow: hidden;

        }
        li {
            list-style: none;
            float: left;
            width: 200px;
            height: 200px;
            background-color: skyblue;
            margin-right: 20px;
        }
        .a .b {
            margin-right: 0px;
        }
        .footer {
            height: 100px;
            background-color: gray;
        }
    </style>
</head>
<body>
    <div class="top">top</div>
    <div class="banner">banner</div>
    <div class="a">
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li class="b">4</li>
    </div>
    <div class="footer">footer</div>
</body>
</html>